The present invention relates to a process for purifying propylene oxide. More particularly, the present invention relates to a process for removing efficiently impurities which exist in propylene oxide to be purified, especially, a process for purifying propylene oxide, which has a feature that impurities which contain an oxygen atom (hereinafter, may be referred to as xe2x80x9coxygen-containing impuritiesxe2x80x9d) can be removed very efficiently.
As a purification process of propylene oxide, a process in which water and a hydrocarbon having 8-10 carbon atoms are used as an extractant, an impurity of a hydrocarbon having 6 carbon atoms contained in propylene oxide is transferred to an oil layer, and a propylene oxide aqueous solution of a water layer is distilled, is known (JP05-170755A). Moreover, a process of distilling an alkylene glycol having 2 to 6 carbon atoms as an extractant is also known (U.S. Pat. No. 5,354,431). However, these processes were insufficient from a viewpoint of removing oxygen-containing impurities efficiently and economically.
Under the present situation, an object of the present invention is to provide a process for purifying propylene oxide, which has a feature that impurities exist in propylene oxide to be purified can be efficiently removed, especially oxygen-containing impurities can be very efficiently removed.
That is, the present invention relates to a process for purifying propylene oxide, which comprises distilling propylene oxide containing impurities in the presence of a hydrocarbon having 5 carbon atoms or less.